# 检查用户名和PIN码
database = [
 ['albert', '1234'],
 ['dilbert', '4242'],
 ['smith', '7524'],
 ['jones', '9843'],
 ['刘翔宇','2120']
]
username = input('User name: ')
pin = input('PIN code: ')
if [username, pin]  in database: print('Access granted')
#如果不添加not in ，在输入错误的情况下则不会输出任何东西，自己尝试一下 not in
if [username, pin]  not in database: print('Access banned')
#注意一下是冒号连接